基于科赫分形的新型超材料双频吸收器  

Study on a novel dual-band metamaterial absorber by using fractal Koch curves

作　　者：马岩冰 张怀武[1] 李元勋[1,2] 

机构地区：[1]电子科技大学,电子薄膜与集成器件国家重点实验室,成都610054 [2]电子科技大学,电子信息工程研究院,东莞523808

出　　处：《物理学报》2014年第11期314-320,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60721001;51132003;61171047);国家自然科学基金青年科学基金(批准号:61001025);广东省国家科技发展规划(批准号:2010B090400314)资助的课题~~

摘　　要：本文提出了一种基于科赫(Koch)分形结构的新型超材料双频吸收器,其由二阶科赫分形阵列、介质层和金属背板三部分组成.通过利用分形结构的空间填充性,其单元尺寸在相同吸收频率下相对于具有正方形谐振结构的传统吸收器有近17.5%的尺寸缩减.与传统实现多频工作的组合法、层叠法不同,该型吸收器的双频特性来源于科赫分形曲线在电磁波激励下呈现出的两种不同的谐振模式.而且由于结构上具有旋转对称性,该型吸收器对入射波的极化方向不敏感,在横电波、横磁波大角度入射时仍能保持较高的吸收率.文中采用等效介质理论对该型吸收器进行了分析,测量结果与仿真结果取得了较好的一致性.In this paper we present a novel dual-band metamaterial absorber（MA）, which is composed of a periodically arranged 2nd order Koch curve array and a metal ground separated by a dielectric spacer. By employing the fractal characteristic of space-filling, more compact unit cell with a size reduction of 17.5% has been achieved as compared with the conventional square-shaped MA. The dual-band operation is not originated from the hybrid or stacked methods as reported before, but from the two distinct resonance modes of the 2nd order Koch curves induced by the incident electromagnetic wave, and can be realized within a single unit cell. Due to its rotationally symmetric pattern, the absorptivity of the above presented MA is insensitive to the polarization of the incident waves and can perform well in a wide range of incident angles. The effective medium theory has been employed to investigate the underlying physical mechanism of the fractal MA, and good agreements between simulation and experimental results have been achieved.

关 键 词：超材料 吸收器 分形 

分 类 号：O441[理学—电磁学]